what is your top speed, prop setup for 272 owners
02-01-2002, 03:56 PM
#1
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what is your top speed, prop setup for 272 owners
I have an 88 272SR1 with twin 330's. boat is ORIGINAL with 310 hrs. top speed is 64.99999mph with 25 pitch quicksilvers. I don't have tons to spend and would like to keep the "originalness" of the boat. looking to do a few little things to break 65 and approach 70. considering labbing the 25's, drilling "small" holes in the silent thunder baffles, and maybe sharpening the transom.
any 272 owners, what is your top GPS speed, what props, and what mods have you done
thanks
any 272 owners, what is your top GPS speed, what props, and what mods have you done
thanks
02-02-2002, 02:34 AM
#3
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I've got an 89 with stock 330's. Best I've seen is 63.9 on GPS with Mirage Plus 23". I bought it 2 years ago with 295 hrs, 423 hours now. I've got a pair of 25's that I haven't tried, mostly because one is a Mirage+ and the other is a plain Mirage.
My platform was modified before we bought it. The baffles on the outer two silent thunder chambers were removed, and on the inner two, a 3" hole was drilled in the bottom to let the water drain out. I have no idea if that helps top end, but it sounds a little louder than others I've seen at idle. If you're at 64.9999 and you want to break 65, you could probably get that .0001 mph by ducking under the windshield. Or running with nothing in the boat except flares and a life jacket. What I've heard about getting props labbed is that they will spin 200-300 rpms more, which might give you a few MPH.
My platform was modified before we bought it. The baffles on the outer two silent thunder chambers were removed, and on the inner two, a 3" hole was drilled in the bottom to let the water drain out. I have no idea if that helps top end, but it sounds a little louder than others I've seen at idle. If you're at 64.9999 and you want to break 65, you could probably get that .0001 mph by ducking under the windshield. Or running with nothing in the boat except flares and a life jacket. What I've heard about getting props labbed is that they will spin 200-300 rpms more, which might give you a few MPH.
02-02-2002, 08:41 AM
#4
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I've got an 89 with stock twin 454Mags 350HP with 330hrs the best I've seen is 66 on GPS with Mirage 23" (not plus). I've have tried a pair of 25” Mirage Plus but I actually loose 1-2 mph with these. The results with these 25’s might be misleading as the owner of these props sharpened them and I am not sure weather it helped or hurt performance. My silent thunder exhaust is completely stock so far.
I have a pair of IMCO 2” shorter lower units on the way and hope to see a few mph increase from this. The next steps after this for me are: install some roller rocker, stainless crossovers and then some lab-finished props. With this combination I hope to be in the low 70s. Down the road I also plan to replace the exhaust manifolds with some from Stainless Marine I understand they save 97lbs per engine and I would like to lighten up my stern as much as practical.
I have a pair of IMCO 2” shorter lower units on the way and hope to see a few mph increase from this. The next steps after this for me are: install some roller rocker, stainless crossovers and then some lab-finished props. With this combination I hope to be in the low 70s. Down the road I also plan to replace the exhaust manifolds with some from Stainless Marine I understand they save 97lbs per engine and I would like to lighten up my stern as much as practical.
02-02-2002, 09:27 AM
#5
Charter Member #232
Charter Member
Cayformula: I would look into putting a crossover on your stock motors. They are ussually only good to use when you put blowers on there. You may run into problems. If you find one that works well on a stock motor then please let us know.
Jon
Jon
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